Within the field of metal cutting operations using cutting tools with cutting inserts, developments have been made to perform a cutting operation where the cutting insert can be rotated about its own axis during engagement with a workpiece to provide a changing portion of its cutting edge without the need for stopping the cutting operation and indexing or replacing the cutting insert. This can avoid a build up of excessive heat at a specific point along the cutting edge which may cause rapid wearing and reduced life of the cutting insert.
U.S. Pat. No. 5,478,175 discloses a milling cutter having a plurality of cutting inserts, each assembled by means of a bushing and spring clip within a single cavity of a cutting tool, before the cutting tools are in turn mounted onto a tool holder. Each cutting insert has a shaft portion and a cylindrical shaped head of larger diameter with a circular cutting edge, and each cutting insert is free to rotate about its own axis within the cutting tool cavity. The top surface of the cutting insert includes a series of serrations and raised obstructions having rotational symmetry about the cutting insert axis, which come into contact with cutting chips being sheared from a stationary workpiece during a cutting operation. The interaction of the cutting chips with the serrations and raised obstructions induces rotation of the cutting insert about its axis causing a continuously changing portion of the cutting edge to engage the workpiece during a cutting operation.
U.S. Pat. No. 7,156,006 discloses a cutting tool assembly for turning operations having a single cutting insert rigidly secured to a tool holder and rotational about its own central axis. Several types of cutting insert are disclosed having continuous cutting edges formed at the intersection of a top surface and a side surface, with chip breaking features on the upper surface exhibiting rotational symmetry about the central axis. The cutting tool assembly is rotated at a predetermined speed by means of an external drive mechanism, which operates independently from a rotating workpiece and ensures that the cutting edge is consistently refreshed during a cutting operation, throughout a wide range of cutting conditions.
JP 6,023,603 discloses a cutting tool having a cylindrical shaped throwaway tip which rotates as a result of cutting resistance generated by contact with a rotating workpiece or by external means. One embodiment of this prior art publication discloses a throwaway tip with a chip breaker formed as a groove in its upper surface, having an elliptical shape in a top view, and exhibiting rotational symmetry. A chip deflection distance between the cutting edge and the chip breaker continuously changes as the throwaway tip rotates, varying from a maximum value to a minimum value and vice versa through 90° of rotation. Another embodiment of this prior art publication discloses a throwaway tip with a chip breaker formed as a groove in its upper surface, having an annular shape in a top view, and exhibiting rotational asymmetry. A chip deflection distance between the cutting edge and the chip breaker continuously changes as the throwaway tip rotates, varying from a maximum value to a minimum value and vice versa through 180° of rotation.